|Publication number||US7142424 B2|
|Application number||US 10/835,852|
|Publication date||Nov 28, 2006|
|Filing date||Apr 29, 2004|
|Priority date||Apr 29, 2004|
|Also published as||US20050243514|
|Publication number||10835852, 835852, US 7142424 B2, US 7142424B2, US-B2-7142424, US7142424 B2, US7142424B2|
|Inventors||Christopher G. Malone, Glenn C. Simon|
|Original Assignee||Hewlett-Packard Development Company, L.P.|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (27), Referenced by (15), Classifications (28), Legal Events (5)|
|External Links: USPTO, USPTO Assignment, Espacenet|
Electronic systems and equipment such as computer systems, network interfaces, storage systems, and telecommunications equipment are commonly enclosed within a chassis, cabinet or housing for support, physical security, and efficient usage of space. Electronic equipment contained within the enclosure generates a significant amount of heat. Thermal damage may occur to the electronic equipment unless the heat is removed.
As electronic components and subsystems evolve to increasing capability, performance, and higher power, while reducing size and form factor, efficient and cost-effective removal of excess heat is desired. Among available thermal management solutions, liquid cooling via cold plate technology offers high capacity for heat rejection and movement of heat from internal sources to external ambient air. Liquid cooling loop systems typically cycle pumped coolants continuously, conveying excess heat from heat-generating devices. The heat is dispersed into ambient air using a heat exchanger or other device.
In accordance with an embodiment of an electronic liquid cooling system, a heat exchanger includes a tube, and a plurality of fins coupled to the tube having a curved fan-stator shape that facilitates straightening of airflow from a fan.
Embodiments of the invention relating to both structure and method of operation, may best be understood by referring to the following description and accompanying drawings.
Compact electronic devices and systems, such as server architectures, may use a liquid loop cooling solution to accommodate increasing power and power density levels for microprocessors and associated electronics. Liquid loops can use a pump to drive cooling fluid through high pressure-drop channels of the colds plates attached to processors and other high-power components and along potentially long and narrow-diameter tube completing the loop between the cold plate, condenser, and pump. Heat is removed from the loop by forced-air convection at the heat exchanger.
Various embodiments of a disclosed electronic system and liquid loop cooling system describe a heat exchanger with fins configured to straighten airflow for optimized fan performance. The heat exchanger and fins can further be configured for acoustic noise reduction.
Curvature of the fins 104 can have a form selected to accept and straighten a vector of air leaving an axial flow fan. Curvature straightens the air into alignment with the axis of the fans. In some embodiments, curvature of the fins 104 is selected to vary in correspondence with radial distance from a central axis of an axial flow fan.
The plurality of fins 104 can be arranged in a stack of mutually parallel, closely-spaced curved plates 108.
The fins 104 can be bent or otherwise formed into the curved shape, generally prior to attachment to the tube 102.
The assembly 200 depicts an example arrangement of the heat exchanger 202 and cooling fans 208, 210 including redundant fans arranged on either side of the heat exchanger 202. In the illustrative arrangement, the heat exchanger fins 206 are planar and aligned with airflow direction. The heat exchanger and fan arrangement improves performance in at least two aspects, acoustical noise reduction and flow straightening.
Fans positioned in close proximity often generate annoying tones. Noise avoidance can be difficult in modem computer systems due to a strong market preference for system compaction, for example leading to reduction in computer chassis dimensions. Positioning of the fans 208, 210 on either side of the heat exchanger 202 attains a desired separation without wasting space. Accordingly, multiple pairs of opposing fans 208, 210 can be connected to opposing sides of the heat exchanger 202 with the fans 208, 210 abutting opposite sides of the heat exchanger 202. In some arrangements, the thickness of the heat exchanger 202 and separation of the opposing fans 208, 210 is selected to reduce acoustical noise.
Air exiting a typical tube-axial fan has a significant radial component. If fans are arranged in series for redundancy, downstream fan performance can be significantly impacted because air entering the downstream fan receives airflow with an off-axis directional component. The effect can be mitigated by separating the fans by a significant distance, although at the cost of potential system compaction or size reduction. By placing the fans 208, 210 on either side of the heat exchanger 202, fins 206 straighten the airflow, thereby improving performance of the downstream fan 210. Straight fins at any suitable orientation attain performance improvement. Accordingly, the fins 206 are formed into a shape that facilitates straightening of airflow from an upstream fan 208 and improves performance of a downstream fan 210. For example, curvature of the fins 206 can have a form selected to accept and straighten a vector of air leaving an axial flow fan.
Additional enhancement in fan performance can be attained by usage of curved fins in the heat exchanger. A fin can be shaped to attain stator functionality. Referring to
A further usage of curved heat exchanger fins enables alignment of airflow directly to downstream components. In some embodiments, downstream fans can be positioned between two banks of curved fins, causing air exiting the heat exchanger to be aligned with the fan axis. Eliminating a radial airflow vector component results in increased cooling of downstream components because airflow can be directed to specific locations, for example to particular heat-generating components. Referring to
The width of the heat exchanger 504 determines the separation between the opposing fans 510 and 512. Fans can generate annoying noises if positioned in too close proximity. The width can be selected to separate the fans sufficiently to reduce acoustical noise. Positioning the fans 510 and 512 on opposing sides of the heat exchanger 504 attains a desired separation without wasting space interior to an electronic system.
The illustrative liquid loop cooling system 500 has multiple fans 510 and multiple fans 512 coupled to and abutting each of the opposing sides of the heat exchanger 504. The number of fans on each of the two sides of the heat exchanger 504 is selected in various designs. For example, some arrangements may include only a single fan 510 and a single fan 512. Typically the fans 510 and 512 have similar or identical sizes and geometry, although in some configurations the sizes and geometry may be different among the multiple fans.
The liquid loop cooling system 500 may further include mounts 530 capable of holding the fans 510, 512, a plurality of cold plates 532 coupled to the tubing 502 and capable of addition and removal via quick disconnect connectors 534. A typical example of a cold plate 532 is a flat metal plate with a series of channels on one or both sides. A length of serpentine tubing can be secured within the channels to contain the liquid coolant flows. Fittings at the inlet and outlet of the tubing connect to the tubing 502. Common tubing materials are copper and stainless steel. Components may be mounted on one or both sides of a cold plate 532.
The illustrative dual-pass liquid-to-air heat exchanger 524 has the form of a flattened tube 526A, 526B for carrying a cooling liquid with fins 528 soldered or braised to the tube. In the illustrative embodiment, two separate sets of fins are used, one attached to a first tube segment and a second attached to a second tube segment. The flattened-tube heat exchanger 524 enables a large variety of arrangements, sizes, and configurations, simply by selecting the sizes, geometry, and topology of fins and tube.
In some embodiments, the heat exchanger 524 can have the form depicted in
Airflow through a heat exchanger can be improved using a heat exchanger 100 of the type shown in
Various electronic system embodiments may utilize a single pair of opposing fans 706 or multiple associated fan pairs on the opposite sides of the heat exchanger 702. In various embodiments, the electronic system 700 may be configured with a heat exchanger and associated fins on only one side of the downstream fans as shown in
The illustrative electronic system 700 includes a heat exchanger 702 with multiple fins 704 having a curved fan-stator shape that facilitates straightening of airflow from an upstream fan of the opposing fans 706. The curved fins 704 have a shape that can be selected to deflect air flow from the fans 706 most appropriately to straighten the airflow vector received from the fans 706, thereby producing an increased or optimum cooling of components 712 downstream of the liquid loop cooling system 714. In other embodiments, the straight fins can be used to also improve cooling performance although the improvement is generally not as pronounced as the curved-fin system.
The liquid loop cooling system 714 may further includes a plurality of cold plates 720 coupled to the tubing 716 and capable of addition and removal via quick disconnect connectors 722. A typical example of a cold plate 720 is a flat metal plate with a series of channels on one or both sides. A length of serpentine tubing can be secured within the channels to contain the liquid coolant flows. Fittings at the inlet and outlet of the tubing connect to the tubing 716. Common tubing materials are copper and stainless steel. Components may be mounted on one or both sides of a cold plate 720.
The liquid loop cooling system 714 also may include a pump 724 to drive cooling fluid through high pressure-drop channels of the cold plates 720 attached to processors and other high-power components 712 and along potentially long and narrow-diameter tube completing the loop between the cold plate 720, heat exchanger 702, and pump 724. Heat is removed from the loop by forced-air convection at the heat exchanger 702.
Cross-sectional thickness of the heat exchanger 702 can be selected to separate fans 706 on opposing sides of the heat exchanger 702 by a distance that reduces acoustical noise.
The illustrative electronic system 700 and liquid loop cooling system 714 can be configured to direct airflow through the heat exchanger 702 by determining a spatial vector distribution of airflow produced by an axial flow fan 706 and deriving a fin plate shape and configuration for the multiple heat exchanger fins 704 based on the spatial vector distribution that straightens the airflow from the fan 706.
Fins 704 of the heat exchanger 702 may be curved in the manner of a fan stator to enhance fan performance. Referring to
Various shaped fins can be used to straighten airflow from the fans, for example the straight fins illustrated in
Referring again to
In some systems, opposing axial flow fans 706 can be positioned abutting the opposite upstream and downstream sides of the heat exchanger 702.
In some embodiments, an additional downstream heat exchanger can be interposed between the liquid loop cooling system 714 and downstream components 712, abutting a downstream side of the downstream axial flow fans 706.
While the present disclosure describes various embodiments, these embodiments are to be understood as illustrative and do not limit the claim scope. Many variations, modifications, additions and improvements of the described embodiments are possible. For example, those having ordinary skill in the art will readily implement the steps necessary to provide the structures and methods disclosed herein, and will understand that the process parameters, materials, and dimensions are given by way of example only. The parameters, materials, and dimensions can be varied to achieve the desired structure as well as modifications, which are within the scope of the claims. Variations and modifications of the embodiments disclosed herein may also be made while remaining within the scope of the following claims. For example, although particular geometries of the redundant fan and heat exchanger arrangements are shown, other arrangements are possible including additional multiple-pass arrangements in which additional fans, heat exchanger geometries, and heat exchanger segments are added. Also, particular electronic system embodiments are illustrated, for example a computer server. In other embodiments, the external heat exchanger can be employed in other types of electronic systems such as communication systems, storage systems, entertainment systems, and the like.
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|U.S. Classification||361/697, 361/679.54, 165/121, 361/700, 165/104.33, 361/709, 165/41, 361/695, 361/679.48|
|International Classification||F28F1/32, F28F13/06, H05K7/20, F28D11/08, F28F1/24, G06F1/20, F25D9/00, F28D1/047|
|Cooperative Classification||F28F13/06, H05K7/20009, F28F1/24, F28D2021/0031, G06F1/20, F28D1/0478|
|European Classification||F28F13/06, F28F1/24, F28D1/047F2, G06F1/20, H05K7/20B|
|Apr 29, 2004||AS||Assignment|
Owner name: HEWLETT-PACKARD DEVELOPMENT COMPANY, L.P., TEXAS
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:MALONE, CHRISTOPHER G.;SIMON, GLENN C.;REEL/FRAME:015294/0870;SIGNING DATES FROM 20040427 TO 20040429
|Dec 22, 2009||CC||Certificate of correction|
|May 28, 2010||FPAY||Fee payment|
Year of fee payment: 4
|Apr 28, 2014||FPAY||Fee payment|
Year of fee payment: 8
|Nov 9, 2015||AS||Assignment|
Owner name: HEWLETT PACKARD ENTERPRISE DEVELOPMENT LP, TEXAS
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:HEWLETT-PACKARD DEVELOPMENT COMPANY, L.P.;REEL/FRAME:037079/0001
Effective date: 20151027